Best Sony Alpha for ice hockey photos?

I am looking to replace my old Konica Minolta D7. I mostly use the camera for taking pictures of junior ice hockey matches. I use a 70-200mm f2.8 (not high speed sadly) lens. Lighting conditions vary from rink to rink and even within many of the rinks!

My D7 really struggles to keep up with the AF and if I shoot a lot of frames quickly then it takes an age to process the pictures and stops me taking more.

I have narrowed my selection to an A450, A500 or A550 - wish I could afford better, but such is life! - and would value any opinions or insight into what would be the smartest choice.

I always look through the viewfinder, so the LCD screen is oly ever used for checking how the pictures come out.
Key things I need are:
Autofocus that quickly adjusts to the speed of the game and patchy lighting

Ability to shoot continuously to capture sequences or just anticipate a goal or big hit etc.